Brush-lifting mechanism.



c. W.'ST-EEN.

BRUSH LlFTING MECHANISM.

APPLICATlON HLED1UNEI9M914- 1 ,22'8 O Patented June 5, 1917.

UNITED STATES PATENT OFFICE.

GEAR-LES W. STEEN, OF NORWOOD, OHIO, ASSIGNOB TO ALLIS-CHALMEBS MANUFAC- TURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE.

BRUSH-LIFTING MECHANISM.

Specification of Letters Patent.

Patented June 5, 1917.

Application filed June 19, 1914. Serial No. 846,205.

To all whom it may concern.

Be it known that I, CHARLES V. S'rnmv, a subject of the King of Norway, residing at Norwood, in the county of Hamilton and State of Ohio, have invented a certain new and useful Improvement in Brusl1Lifting Mechanisms, of which the following is a specification.

This invention relates in general to dynamoelectric machines, and has particular relation to such machines of the commutator type as require, for efficient operation, a temporary lifting of all or a part of the brushes.

In starting rotary converters having interpoles, from the alternating current side, there may be considerable sparking at the direct current brushes due to the action of the interpoles in increasing the magnetic flux that links the short-circuited coils beneath the brushes, thus increasing the energy of the circuit of these short-circuited coils at the time such circuit is interrupted by the corresponding commutator segments leaving the brushes. By raising all, except a comparatively small number of the brushes, those remaining on the commutator being of comparatively high resistance so as to limit the current to a value just suflicient to establish the direct current field, sparking at the direct current brushes is avoided, or greatly reduced. When the machine is up to synchronous speed, the raised brushes may be lowered to their normal operating condition, in contact with the commutator surface.

Prior to this invention, devices have been used for raising brushes of a dynamo-electric machine from the commutator surface, which devices comprise parts on the brushes and on the actuating mechanism, these parts being normally unconnected, and being brought into operative relation during the first part of the operation of the actuating mechanism of the brush-lifting device. Such an arrangement requires close adjustment of the actuating parts, and it often happens that such parts, on the actuating mechanism and on the brush, work themselves out of alinement, with the consequent result that the effective operating connection is not established, and the brush, consequently, is either imperfectly raised, or not raised at all.

it i an sheet 9? this in asive to p vide an improved construction of brushlifting mechanism that is comparatively simple and efficient in operation, and one that requires comparatively little or no adjustment to compensate for wear of the brushes during the ordinary life thereof, and to provide such a device in which there is a permanent connection between the actuating mechanism and the brush or brushes to be lifted.

This and other objects are attained by this invention, the various novel features of which will appear from the description and drawing, disclosing one embodiment of such invention, and will be particularly pointed. out in the claims.

In the accompanying drawings:

Figure 1 is a view in elevation of a portion of a dynamo-electric machine of the commutator type, with parts in section, the machine being provided with a brush-lifting device in accordance with this invention.

Fi g. 2 is an end view of the brush-holder support and the brush-lifting device shown in Fig. 1, parts being broken away.

Fig. 3 is an enlarged view in elevation of a detail, showing one manner of connecting a portion of the brush-lifting mechanism to a brush.

As shown in the drawings, M represents a dynamo-electric machine, having a field frame F and an armature A, the armature being provided with a commutator C. A bearing B forms one support for the ar mature shaft S.

A supporting frame 11 is mounted, as on a machined portion 12, on the bearing B. In the preferred construction, this supporting frame is in two similar parts held together by bolts 13, which act to clamp the parts together and to secure the frame in fixed position on the bearing B. It will be obvious that, by loosening the bolts. 18, the frame 11 may be angularly adjusted on its support. The supporting frame 11 is, preferably, of as open construction as is consistent with strength to provide a fairly open aXial path to commutator and brushes. Extending axially from the supporting frame 11 and mechanically connected thereto and electrically insulated therefrom, are a plurality of equally spaced brush rods 14 which overlie the commutator C and are equally spaced therefrom. A plurality of brush holders 15 are secured in position on each brush rod 14, and brushes 16 are mounted in guiding recesses in said brushholders 15. In the normal operation of the machine, spring-pressed followers 17, bearing on the outer ends of the brushes 16, act to urge said brushes toward the commutator surface.

To provide for lifting all, or any number of brushes, as may be desirable, from the commutator, each of the brushes to be lifted has secured to it, as by means of a rivet or screw 13, that secures a pig-tail connection 19 to the brush, a washer or piece 21. A chain 23 is secured to the part 21 by a rivet or screw 24.

Supporting members and 26 are held in fiXed position 011 each brush rod 14, the former being held between abutment nuts 27 and 2S, and the latter between a shoulder at the inner end of the brush rod and a securing nut 29. A rod 31 is pivotally mounted in openings at the outer ends of each pair of supporting members 25 and 26, collars 32 and 33 adjacent the member 25, and collars 34 and 35 adjacent the mem ber 26 limiting axial movement of the rods 31 relative to the members 25 and 26. Fixedly secured to each rod 31, are a plurality of arms 37 which project over the brush holders and brushes mounted on the adjacent brush rod 14.

By attaching the other end of chain 23 to an arm 37, it will be obvious that, on the rotation of the rod or shaft 31, the corresponding arm 37 will serve to lift the inner end of the brush 16 away from the commuta tor surface and into its guide. Any suitable connection may be made between the outer end of the chain 23 and the arm 37. As shown, a collar 33, having a rectangular opening through which the end of the arm 37 passes, is mounted on the arm 37 and is held thereon, as by means of a cotter pin 39 which passes through an opening in the arm. The end of the chain may be attached to this loose collar in any suitable manner, as by means of a screw 41.

To provide for the simultaneous operation of all the pivoted rods 31, each of said rods is provided with a bellcrank lever 42. Adjacent bell-crank levers 42 are connected through rods 43; and a lever 45, pivoted at one end to the supporting frame 11 at 46, is loosely attached to one of therods 43. On operation, the lever 45 actuates the rod 43 connected thereto, which in turn actuates the other bell-crank levers 42 and rods 43, these in turn rotating the rods or shafts 31 and actuating the arms 37 to cause the raising or lowering of the brushes through the chains 23.

To determine the raised and lowered positions of the brushes, the lever 45 is provided with a rod 47, spring-pressed in one Fig. 2, the brushes are in engagement with the commutator surface. To raise the brushes, as during the starting operation of the machine, the lever 52 is operated to withdraw the end of the rod 47 from engagement in thenoteh 43 of the part 51, the lever 45 being then operated in an anticlockwise direction to move the rods 43 and the bell-crank levers 42, with their attached rods or shafts 31, in an anti-clocluvise direction, thus actuating the rods 37 in an anticlockwise direction, or away from the commutator surface. This actuation of the arms 37 effects the raising of the brushes 16 in their guides, through the chains The full raised position of the brushes is de termined by the engagement of the end of the spring-pressed rod 47 in the notch 49 of the part 51. The reverse operation of the lever 45 from this position returns the actuating mechanism to normal position, and permits the spring-pressed followers 17, mounted on the brush-holders 15, to return the brushes into engagement with the com-' mutator surface.

In the ordinary operation of dynamoelectric machines of the commutator type, the brushes are not used after the same are about half worn. Hence, by making the brush guides of sufiicient length to effectively guide the brushes, when worn to half their original length, in their necessary movement from the commutator surface, there need be no further adjustment of the connecting chains 23 relative to the arms 37 and the brushes 16, if, when the chains are first attached to new brushes, there is suflicient slack to allow the brushes to contact with the commutator surface when the brushes are in the usual, fullyworu condition. It will be apparent, then, that, with new or slightly worn brushes, the first part of the movement of the arms 37 will take up the slack in the chains 23, and further movement of such arms will lift the brushes from the commutator surface. As the brushes wear, there will be less slack chain to be taken up during the first portion of the raising operation, and the brushes, when in full raised position, will be farther from the commutator surface. However, in case it may not be desirable to allow sufficient slack in the chains to accommodate the entire wear during the life of the brushes without further adjustment, as where the brush-guides are comparatively short, the chains may have comparatively little slack when attached to new brushes and may be gradually lengthened, as to the extent of adding a link at the point of connection of the chains to the collars 38, as the brushes become worn.

The brushes may be insulated from the actuating mechanism in any suitable way, as by making insulating connections between the chains and the brushes or between the chains and the collars 38 on the arms 37; or the raising mechanism for the individual brush rods may be insulated from one another by making the rods 43 of insulating material, or by providing a section of insulating material in such rods.

It should be understood that it is not desired to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In a dynamo-electric machine, a brush holder, a brush mounted thereon and mov able relatively thereto into and out of engagement with a collecting surface, means cooperative with said brush holder and said brush for resiliently urging said brush into engagement with said collecting surface, actuating mechanism, and a permanent flexible connection between said actuating mechanism and said brush and independent of said urging means whereby said brush may be moved relatively to said brush holder and away from said collecting surface.

2. In a dynamo-electric machine, a supporting frame, a brush rod mounted on said frame, a brush holder mounted on said rod, a brush movably mounted on said brush holder, a member rotatably mounted adjacent said brush holder, supporting means for said member secured to said brush'rod, and a permanent operating connection between said rotatably mounted member and said brush, whereby said brush may be moved relatively to said brush holder on the rotation of said member.

3. In a dynamo-electric machine, a sup porting frame, a plurality of circumferentially spaced brush rods secured in operative position on said frame, a plurality of brush holders mounted on each rod, brushes movably mounted in said brush holders, means associated with each of said brush holders for resiliently urging the corresponding brush into engagement with a current collecting surface, movably mounted members supported in operative position by said brush rods, actuating means for said members, and operating connections between said movable members and said brushes and independent of said urging means whereby said brushes are raised on the actuation of said members.

4:. In a dynamo-electric machine, a brush holder, a brush mounted for movement relatively thereto, means for resiliently urging said brush into engagement with a current collecting surface, a member rotatably mounted adjacent said brush holder, a flexible connection between said brush and said member, said connection being fixed at one end to said brush and being adjustably connected at the other end to said rotatable member and being independent of said urging means.

5. In a dynamo-electric machine, a supporting frame, a plurality of circumferentially spaced brush rods secured in operatire position on said frame, a plurality of brush holders mounted on said rods, brushes movably mounted in said brush holders and engageable with a collecting surface of the a machine, means associated with said brush holders for resiliently urging said brushes into engagement with said collecting surface, supports mounted on said brush rods, movable members operatively mounted on said supports, means for mechanically con necting the movable members mounted on the several brush rods for simultaneous operation, and permanent flexible connections between said movable members and said brushes and independent of said urging means whereby said brushes may be moved from engagement with said collecting surface on the actuation of said movable members.

6. In a dynamo-electric machine, brushsupporting means, a brush mounted thereon and movable relatively to a portion thereof into and out of engagement with a collecting surface, means cooperative with said brushsupporting means and said brush for resiliently urging said brush into engagement with said collecting surface, actuating mechanism, and a permanent flexible connection between said actuating mechanism and said brush and independent of said urging means whereby said brush may be moved relatively to said portion of said brush-supporting means and away from said collecting surface.

In testimony whereof, the signature of the inventor is affixed hereto in the presence of two witnesses.

CHARLES W. STEEN.

Witnesses:

HENRY C. BEEKLEY, ADAM ITTEL.

Copies of this Patent may be obtained for five cents each, by addres ing 1 19 g m i o Patents Washington, D- Gr 

